ADO accessing database access source code of the image type field

Ado header file code:

# If! Defined (afx_ado_ado_h00009f3bd0b450a877_4b35_9dce_e73e49efe0c500000000ded _)
# Define afx_ado_ado_h00009f3bd0b450a877_4b35_9dce_e73e49efe0c500000000ded _

# If _ msc_ver> 1000
# Pragma once
# Endif // _ msc_ver> 1000

Class ado_ado
{
Public:
_ Connectionptr m_pconnection; // connection object pointer
_ Recordsetptr m_precordset; // record set object pointer
Public:
Ado_ado ();
Virtual ~ Ado_ado ();
Void oninitadoconn (); // connect to the database
_ Recordsetptr & openrecordset (cstring SQL); // open the record set
Void closerecordset (); // close the record set
Void closeconn (); // closes the database connection
Uint getrecordcount (_ recordsetptr precordset); // obtain the number of records
};

# Endif

 

Code of the ADO function implementation file:

# Include "stdafx. H"
// # Include "ADO. H"
# Include "ado_ado.h"

# Ifdef _ debug
# UNDEF this_file
Static char this_file [] =__ file __;
# Define new debug_new
# Endif

//////////////////////////////////////// //////////////////////////////
// Construction/destruction
//////////////////////////////////////// //////////////////////////////

Ado_ado: ado_ado ()
{

}

Ado_ado ::~ Ado_ado ()
{

}
Void ado_ado: oninitadoconn ()
{
: Coinitialize (null); // afxoleinit (); initialize the com Library
/* // "Provider = sqloledb; persist Security info = false; uid = sa; Pwd =;
// Initial catalog = text; Data Source = Lenovo/simple ;"
----- ADO database connection string template for connecting to SQL Server ----------
[1] Authentication Mode: "SQL Server and Windows"
"Provider = sqloledb.1; persist Security info = true; user id = user name; Password = password;
Initial catalog = database name; Data Source = SQL server name"
[2] Authentication Mode: "Windows only"
"Provider = sqloledb.1; Integrated Security = sspi; persist Security info = false;
Initial catalog = database name; Data Source = SQL server name"
"DSN =; uid = sa; Pwd =; server = ntserver; provider = sqloledb; database = text "*/
Try
{
M_pconnection.createinstance ("ADODB. Connection"); // create a connection object instance
_ Bstr_t strconnect = "provider = sqloledb.1; persist Security info = true; user id = sa; Password =; initial catalog = dscdtsdb; Data Source = 192.168.0.125 ";
M_pconnection-> open (strconnect, "", "", admodeunknown); // open the database
}
Catch (_ com_error E)
{
Afxmessagebox (E. Description (); // an error occurs.
}
}
_ Recordsetptr & ado_ado: openrecordset (cstring SQL)
{
Assert (! SQL. isempty (); // The SQL statement cannot be empty.
Try
{
M_precordset.createinstance (_ uuidof (recordset); // create a record set object instance
M_precordset-> open (_ bstr_t (SQL), m_pconnection.getinterfaceptr (),
Adopendynamic, adlockoptimistic, adshorttext); // run the SQL statement to obtain the record set.
}
Catch (_ com_error E)
{
Afxmessagebox (E. Description ());
}
Return m_precordset; // returns the record set pointer.
}
Void ado_ado: closerecordset ()
{
If (m_precordset-> getstate () = adstateopen) // you can determine the status of the current record set.
M_precordset-> close (); // close the record set
}
Void ado_ado: closeconn ()
{
M_pconnection-> close (); // close the database connection
: Couninitialize (); // m_pconnection-> release (); //: couninitialize (); // release the com Environment
}
Uint ado_ado: getrecordcount (_ recordsetptr precordset)
{
Int ncount = 0; // declare the variable that saves the number of records
Try
{
Precordset-> movefirst (); // move the record set pointer to the first record
}
Catch (...) // catch possible errors
{
Return 0;
}
If (precordset-> adoeof)
Return 0;
While (! Precordset-> adoeof)
{
Precordset-> movenext ();
Ncount ++;
}
Precordset-> movefirst ();
Return ncount; // number of returned records
}

 

 

 

ADO object definition

Ado_ado m_ado_dd8tb;

 

Read database code:

M_ado_dcdtb.oninitadoconn ();
Ctime tnow = ctime: getcurrenttime ();
Cstring strcurrday = tnow. Format ("% Y-% m-% d ");
Cstring strsql;
Strsql. Format ("select * From dscdatatb where storage date = '% s' order by storage time", strcurrday );
M_ado_dcdtb.m_precordset = m_ado_dcdtb.openrecordset (strsql );
// Char wendushuju [1, 5120] = {0 };
Char * m_pbmpbuffer = NULL;
_ Variant_t pvlist;
Long ldatasize;
While (! M_ado_dcdtb.m_precordset-> adoeof)
{
Cstring guangxianno = (char *) (_ bstr_t) m_ado_ddxtb.m_precordset-> getcollect ("Storage Time ");
Ldatasize = m_ado_ddxtb.m_precordset-> getfields ()-> getitem (_ variant_t ("temperature data")-> actualsize;
If (ldatasize> 0)
{
_ Variant_t varblob;
Varblob = m_ado_dsp_tb.m_precordset-> getfields ()-> getitem (_ variant_t ("temperature data")-> getchunk (ldatasize );
If (varblob. Vt = (vt_array | vt_ui1 ))
{
M_pbmpbuffer = new char [ldatasize + 1];
Char * pbuf = NULL;
Safearrayaccessdata (varblob. parray, (void **) & pbuf );
Memcpy (m_pbmpbuffer, pbuf, ldatasize );
Safearrayunaccessdata (varblob. parray );
}
}
M_ado_dcdtb.m_precordset-> movenext ();
}